OFFSET
0,5
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..85
FORMULA
a(n) = 2^n - A151897(n). - Andrew Howroyd, Jan 27 2024
EXAMPLE
The a(0) = 0 through a(5) = 10 subsets:
. . . {1,2,3} {1,2,3} {1,2,3}
{1,3,4} {1,3,4}
{1,2,3,4} {1,4,5}
{2,3,5}
{1,2,3,4}
{1,2,3,5}
{1,2,4,5}
{1,3,4,5}
{2,3,4,5}
{1,2,3,4,5}
MATHEMATICA
Table[Length[Select[Subsets[Range[n]], Intersection[#, Total/@Subsets[#, {2, Length[#]}]]!={}&]], {n, 0, 10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Aug 02 2023
EXTENSIONS
a(16)-a(25) from Chai Wah Wu, Nov 14 2023
a(26) onwards (using A151897) added by Andrew Howroyd, Jan 27 2024
STATUS
approved